WGA seeks ways to add renewables

Jul 15, 2012 - Bill Opalka -


Greater amounts of renewable energy are continually being added to the power mix in the Western states, so ways to integrate those resources are paramount.

That’s the advice of a recent report by the Western Governors Association seeking ways to integrate wind, solar and geothermal power more seamlessly into the gird. The report suggests operational changes that would accommodate more renewable energy while seeking to minimize any impacts on costs.

The WGA estimates renewable resources will double from 2010 levels to 2022 as renewable portfolio standard requirements increase over the next decade are added.
“Integrating these resources into a reliable and affordable power system will require an unprecedented level of cooperative action within the electric utility industry and between the industry and state, subregional and federal entities,” the report says.

The flexibility is largely unused. Other regions of the country have found ways to increase flexibility and efficiency from supply- and demand-side resources and transmission, although the West faces some unique challenges.

While most transmission in the Western Interconnection is scheduled in hourly intervals, output from variable energy resources changes within the hour. Greater use of subhourly dispatch and intra-hour scheduling in the West’s bilateral markets could allow generators to schedule their output over shorter intervals and closer to the scheduling period, effectively accessing existing generator flexibility that is not available to most of the West today.

This would reduce the amount of required regulation reserves, for example.
However, there are up-front costs to move to intra-hour scheduling, the report notes.

Other recommendations include:

  • Consider strategies for assisting smaller transmission providers to recover costs of transitioning to intra-hour scheduling, such as coordinated operations among multiple transmission providers or phasing in equipment and personnel upgrades over multiple years.
  • Explore harmonized implementation of faster dispatch, scheduling, balancing and settlement across the Western Interconnection.
  • Allow regulated utilities to recover costs for wind integration charges assessed by a third party at the lesser of the rate charged for intra-hour scheduling or hourly scheduling, if intra-hour scheduling.
  • Grant cost recovery for software upgrades and additional staff necessary to accommodate intra-hour scheduling.

Implementation barriers cited are upfront financing and accepting and adapting to a new operational practice. Choosing a market operator, governance, a market monitor to prevent and mitigate potential market manipulation, coordination agreements with reserve sharing groups, and agreements with non-participants are challenges. Uncertain participation is another barrier.

Another requirement is improved forecasting for wind and solar integration. Improvements in the foundational forecasts that variable generation forecasters rely upon will improve the quality and accuracy of variable generation forecasts, the report says.